Tonsiki 360 Pcs 8-25mm Stainless Steel Watch Band Spring Bars Link Pins Material: durable stainless steel 18 different sizes: 8 mm, 9mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm. Pins used for metal watch strap links,connect the watch band to the case or buckle,easy to install Those watch link pins are kept in a transparent plastic box for keeping the 18 different sizes separated and easy to access.